ASTM A312 TP347 — Chemical Composition & Mechanical Properties
ASTM A312 TP347 is a austenitic stainless steel grade for seamless & welded pipe (UNS S34700, EN / W.Nr 1.4550). This sheet summarises its chemical composition limits, minimum mechanical properties, heat treatment and typical service. Teshi Group supplies this grade as a stockist and supplier, and manufactures matching flanges and fittings.
ASTM A312 TP347 at a glance
| Specification | ASTM A312 TP347 |
|---|---|
| Material family | Austenitic stainless steel |
| Product form | Seamless & welded pipe |
| UNS number | S34700 |
| EN / W.Nr equivalent | 1.4550 |
| Also known as | 347 |
| PREN (min values) | 17.0 |
| Document | TG-MG-058 · Rev. 1 · October 2026 |
Typical service
Niobium-stabilised stainless piping
Heat treatment
Solution annealed 1040 °C min, rapid cool
Chemical composition of ASTM A312 TP347 (weight %)
Other elements and limits: Nb 10×C min, 1.10 max
Single values are maximums unless shown as a range or “min”.
Mechanical properties
| Tensile strength, min | 515 MPa |
|---|---|
| Yield strength (0.2 % offset), min | 205 MPa |
| Elongation, min | 35 % |
| Hardness | Not specified |
About austenitic stainless steel
Austenitic stainless steels are iron–chromium–nickel alloys with 16–26 % chromium and 8–22 % nickel. Nickel keeps the structure austenitic (face-centred cubic), which makes these steels non-magnetic when annealed, very tough down to cryogenic temperatures, and easy to form and weld.
Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.
International equivalents of ASTM A312 TP347
All equivalents| Standard system | Nearest equivalent grade |
|---|---|
| USA — ASTM / ASME | ASTM A312 TP347 · ASME SA-312 TP347 |
| USA — UNS | S34700 |
| Europe — EN designation | X6CrNiNb18-10 |
| Europe — W.Nr | 1.4550 |
| Japan — JIS | SUS347 / SUSF347 |
| China — GB / NB | S34778 (06Cr18Ni11Nb) |
| China — old GB designation | 0Cr18Ni11Nb |
| India — IS | X04Cr18Ni10Nb (IS 6911) |
| UK — BS (withdrawn) | 347S31 |
Equivalents are the nearest commonly cited grades. Chemistry, mechanical properties and testing differ between standards — compare them before substituting one for another.
Same alloy in other product forms
| Product form | Specification / grade |
|---|---|
| Forged flanges & fittings | ASTM A182 F347 |
| Wrought butt-weld fittings | ASTM A403 WP347 |
Standards for ASTM A312 TP347
All material standardsFAQ
ASTM A312 TP347: common questions
What is the minimum yield strength of ASTM A312 TP347?
205 MPa, with a minimum tensile strength of 515 MPa.
What is the carbon content of ASTM A312 TP347?
0.08 max %.
What is the PREN of ASTM A312 TP347?
About 17, calculated as Cr + 3.3Mo + 16N using the specification minimum values. Typical heats are a little higher.
What is the UNS number and EN equivalent of ASTM A312 TP347?
UNS S34700; the nearest European designation is W.Nr 1.4550. Equivalents are close but not identical — check the specification if substituting.
How is ASTM A312 TP347 heat treated?
Solution annealed 1040 °C min, rapid cool.
What is the Chinese (GB) equivalent of ASTM A312 TP347?
The nearest Chinese equivalent is S34778 (06Cr18Ni11Nb), formerly 0Cr18Ni11Nb. Equivalents are close but not identical — compare chemistry and properties before substituting.
What is the JIS equivalent of ASTM A312 TP347?
The nearest Japanese (JIS) equivalent is SUS347 / SUSF347.
Does Teshi Group supply ASTM A312 TP347?
Teshi Group supplies this grade as a stockist and supplier, and manufactures matching flanges and fittings. Send your size, rating and quantity to info@teshigroup.com for a quotation with EN 10204 3.1 certificates.
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